Stabilizing hydrocracked lubricating oils

ABSTRACT

The instability of lubricating oils to light and air formed by hydrocracking high boiling fractions is removed by percolating the oil through silica-alumina gels containing a Y-type molecular sieve.

United States Patent MacDonald et al.

[451 June 20, 1972 [54] STABILIZING HYDROCRACKED LUBRICATING OILS [72]Inventors: John M. MacDonald; Ian D. Campbell,

both of Sarnia, Ontario, Canada [73] Assignee: Esso Research andEngineering Company [22] Filed: March 16, 1970 [21] Appl. No.: 20,134

52 05.0 ..208/97, 252 412, 208/99 511 int. Cl [58] FieldolSearch..208/99,97,96,l8,28

Primary Examiner-Delbert E. Gantz Assistant Examiner-G. J. CrasanakisAttorney-Pearlman and Stahl and C. D. Stores ABSTRACT The instability oflubricating oils to light and air fonned by hydrocracking high boilingfractions is removed by percolating the oil through silica-alumina gelscontaining a Y-type molecular sieve.

16 Claims, No Drawings STABILIZING HYDROCRACKED LUBRICATING OILSBACKGROUND OF THE INVENTION This invention relates to the preparation oflubricating oils stable to light and air.

For many years, lubricating oils have been obtained from crude oils ofvarious character mainly by separation processes. In order to obtainlubricants of relatively high viscosity index (V.l.), it has been thepractice to subject the oils fractionated from the crude to solventextraction to remove components serving to lower the V.I. The solventextracted lubricants are naturally resistant to degradation in light andair; however, they are generally fortified with one or more additives inorder to improve their resistance to oxidation during use and the like.

Recently it has been discovered that lubricating oils may be produced byhydrocracking. In this conversion process, a heavy petroleum oil iscontacted with hydrogen at elevated temperature and pressure in thepresence of 'a hydrocracking catalyst. The hydrocracked product isseparated into materials boiling in different temperature ranges,including the lubricating oil boiling range, i.e., oils boiling above650 F. The lubricating oil fractions differ from those obtained byfractional distillation of crude oils and the like, since they haverelatively high V.l. values and thus do not require solvent extractionto enhance their V.l. values.

Unfortunately, however, such lubricating oil fractions suffer from theshortcoming that they are unstable when exposed to light (particularly,actinic rays) and air. When so exposed, sediment, sludge, and lacquerformation occur. There is also a marked darkening in the color of theoil. All of this results in the lessening of the commercial value ofsuch lubricants.

SUMMARY OF THE INVENTION It has now been discovered that whenlubricating oils produced by hydrocracking are percolated throughsilica-alumina gels containing a Y-type molecular sieve, there isobtained an unexpectedly high yield of significantly more stable premiumgrade oil. It appears that the oxide gel containing the zeoliteselectively removes the instability-causing compounds from thehydrocracked product without affecting the desirable lubricating oilcomponents.

Broadly stated, this invention comprises subjecting a lubricating oilfraction which is unstable to light and air to a treatment whichcomprises percolating it through a column of a silica-alumina gelcontaining a Y-type zeolitic sieve. Such zeolitic materials are commonlyused as fluid catalytic cracking catalysts. More specifically theinvention covers contacting a high boiling hydrocarbon material withhydrogen in the presence of a hydrocracking catalyst at a temperature inthe range of 700 to 900 F. and at an elevated pressure in order toconvert at least weight percent of the high-boiling hydrocarbons toproducts boiling below 650 F., recovering a lubricating oil fraction andpercolating said lubricating oil fraction through a column of a zeoliticfluid catalytic cracking catalyst.

DESCRIPTION OF SPECIFIC EMBODIMENTS Hydrocarbon Feed The hydrocarbonfeed material or fractions which can be hydrocracked as describedherein, can be substantially any hydrocarbon feed material susceptibleto treatment with hydrogen. Generally, however, it is preferred to usehigh boiling range materials derived from petroleum crude oils, boilingabove about 650 F., e.g., heavy gas oils, residual stocks, cycledstocks, topped crudes, reduced crudes, deasphatled residua, andrelatively high boiling hydrocarbon fractions derived from coal, tars,pitches, asphalts and shale oils. These materials can be obtained byfractionation, as by vacuum distillation, or crude oils identified bytheir source, viz: Pennsylvania, Mid-Continent, Gulf Coast, West Texas,Western Canada, Venezuela, Amal, Kuwait, Barco, Safaniya, Alaskan, etc.

Hydrocracking Catalyst The catalyst employed in the hydrocrackingreaction may include any type of hydrogenation catalyst having crackingactivity. Accordingly the catalysts may include the oxides and sulfidesof the metals of Group VlB of the Periodic Table or mixtures, thereof,such as chromium sulfide, molybdenum sulfide and tungsten sulfide;oxides and sulfides of Group VIII of the Periodic Table or mixturesthereof, such as sulfides of iron, cobalt, nickel, palladium, platinum,rhodium, osmium, and iridium; mixtures of the above oxides and sulfidesof the metals of Group VB, VlB, and VIII such as mixtures of nickelsulfide and tungsten sulfide, cobalt and molybdenum oxide or sulfide.The hydrogenating component is deposited on a cracking component,preferably containing a siliceous cracking component such assilica-alumina, silica-magnesia, silica-zirconia, andsilica-alumina-zirconia. A zeolitic cracking base may be used instead.For example, a particularly effective hydrocracking catalyst comprises apalladium hydrogenation component composited with a hydrogen faujasitecracking base. Another suitable catalyst comprises a mixture of GroupVIB and VIII non-noble metals, such as nickel and tungsten supported ona hydrogen form of crystalline aluminosilicate zeolite with or withoutclay.

Hydrogen Pure hydrogen can be used. However hydrogen of lower purityobtained by recycle from other hydrogenating process or from otherrefining operations, e.g., reforming, may be used. The hydrogen may becirculated at a rate in the range of from about 1,000 to 20,000 standardcubic feet per barrel of hydrocarbon charge and preferably 5,000 to20,000 standard cubic feet per barrel of charge. A hydrogen consumptionof 1,000 standard cubic feet per barrel of feed is preferred but muchmore or less may be used.

Hydrocracking Conditions The hydrocarbon feed is contacted with hydrogenand a catalyst of the character described above, at a temperatureranging from 500 to 1,000 E, preferably 700 to 900 F. and morepreferably below 850 F. The pressure nonnally ranges above 1,500 psigand the hydrocarbon reactant space velocity through the catalyst isbelow 1.0 liquid hourly space velocity (V/V/Hr.). It is preferred tomaintain the pressure above 2,000 psig, the temperature below 850 F. andthe space velocity between 0.1 and 0.75.

The reaction may be carried out in any of the suitable equipment wellknown in the art for such catalytic operations and may be either batchor continuous. Conversions may range from 10 to 75 percent by volume ofproducts boiling below 650 F.

Hydrogenated Product Fractionation Following the hydrocracking reaction,products are withdrawn and passed through a heat exchanger or othersuitable cooling device, where they are cooled to a temperature wherehydrogen gas can be separated. The cooled effluent is then passed into ahigh pressure gas separator from which the gases are removed and theliquid product is passed to a fractionator from which several fractionsare obtained, including lubricating oil fractions boiling above 650 F.

The lubricating oil fractions may be dewaxed, if desired, by anyconventional method to provide an oil having a pour below about 30 F.

The Percolating Step The hydrocracked lube oil is then percolatedthrough a column of a zeolite containing fluid catalytic crackingcatalyst. The percolating step is best carried out at room temperaturebut any temperature up to l50 F. can be used. Higher temperatures do notgive the desired results.

The zeolitic material through which the oil is percolated may containany Y-zeolites, i.e., a zeolite having a silica/Alp; ratio greater than3/1. Suitable zeolitic material includes a physical mixture of aconventional amorphous cracking catalyst containing a major amount ofsilica and a minor amount of alumina and a crystalline alumina-silicatezeolite in a siliceous matrix, e.g., faujasite having uniform poreopenings of about 6 to 15 Angstrom units. A particularly suitablecatalyst consists of percent of a mixture of 13% Alp; and

87% SiO, with 5 percent of 13 Y-zeolite or faujasite. The zeolite-y isfirst ammonia exchanged, then spray dried and then rare-earth exchanged.These catalysts are described in application Ser. No. 744,287 filed June12, 1968 for Robbins et al. which is incorporated herein by reference.

Illustrative Examples The following examples illustrate and, in nosense, limit the invention.

EXAMPLE 1 A West Texas feedstock consisting of a blend of deasphaltedresiduum and high vacuum gas oil was hydrocracked at 780 F., 0.5 liquidhourly space velocity and 2,500 psig over a sulfided commercialhydrocracking catalyst. A IO-grade lube distillate fractionated from thehydrocracked blend was dewaxed to give an oil having the followingproperties:

Viscosity at 100F. I50 SUS Viscosity Index I Pour Point +F. Color (T.R.)9%

This distillate was percolated through a bed of silica gel, a bed ofalumina, a bed of Filtrol clay, and a bed of a cracking catalystcontaining 95 wt.% SiO,-Al,0; in the proportion of 13% A1 0, and 87%SiO,, and 5 wt. percent of a l3-Y zeolite, with heptane as a solvent.The treated oils were then exposed to daylight in clear glass 4 ouncebottles in the presence of air at room temperature. The following datawere obtained.

TABLE 1 Stabilization of Hydrocracked Lubes By Percolation ConditionsISONeutral Oil (1 Part W.) Diluted with l-leptane (1 Part W.) andPercolated through Absorbent (1 Part W.). Column Washed with Heptane (4Parts W.).

Yield Days in Absorbent of Oil Oil Color window until (Wt. (Saybolt)sludge formation Untreated Oil 9%T.R. 2 Cracking Catalyst 97 +35 100Silica Gel 95 +30 11 Alumina (Neutral) 98 +30 l2 Filtrol Clay 98 +16 8The above data show that percolation through silica gel, alumina orFiltrol clay improved the color of the oil significantly but thedaylight stability was increased to only 8 to 12 days, while percolatingthrough the cracking catalyst caused the daylight stability to increaseto more than 100 days. A conventional solvent-extracted 150 N lube froma similar crude source has a daylight stability of 21 days.

EXAMPLE 2 The experiment of Example 1 was repeated using the same 150 Noil but varying the adsorbent to feed ratio. The following data wereobtained.

TABLE 2 Stabilization of Hydrocracked Lubes by Percolation Conditions150 Neutral Oil (1 Part W.) Diluted with Heptane (I Part W. andPercolated Through Cracking Catalyst. Adsorbent then Washed withHeptane.

Absorbent to Yield of Days in Feed Oil Ratio Treated Oil window until(by) weight) (Wt. sludge formation The above data show that the daylightstability decreases with decrease in adsorbent to feed oil ratio. A feedoil rau'o of less than 0.3 is not suitable if a highly stabilized oil isdesired.

Adsorbent to Yield of Days in feed oil ratio treated oil window until(by weight) (wt sludge formation EXAIVIPLE 3 The experiment of Example 1was repeated and the adsorbent was regenerated by washing with benzene.The regenerated adsorbent was used to treat additional samples of feed.The following data were obtained.

TABLE 3 Stabilization of Hydrocracked Lubes by Percolation Regenerationof Adsorbent by lnterpercolation Washing Conditions Neutral Oil (1 PartW.) Diluted with Heptane (1 Part W.) and Percolated through 3B-2Cracking Catalyst (1 Pan W.). Column then Washed with Heptane (4 PartsW.) and Regenerated with Benzene Wash (5 Parts W. Cycle then repeated.

Yield of Days in Cycle Treated Oil Window until (Wt.%) Sludge FormationFeed 2 l 97 54 2 89 N/A 3 96 53 4 96 40 8 96 41 The above data show thatthe adsorbent column can be repeatedly regenerated by benzene washingand that the hydrocracked oil treated by the regenerated adsorbent wasmore stable than the conventional reference oil even alter the adsorbentcolumn used to treat the hydrocracked oil had been regenerated severaltimes.

EXAMPLE 4 The experiment of Example 1 was repeated using a series ofhigher viscosity hydrocracked oils as feed. The following data wereobtained.

TABLE 4 Stabilization of Hydrocracked Lubes by Percolation CONDITIONS:AS IN TABLE 2.

The above data show percolation of higher viscosity grade hydrocrackedlubes from the same crude also gave stable oils of much improved color.

EXAMPLE 5 The hydrocracked oil of Example 1 was slurried with thecracking catalyst adsorbent, with charcoal and with F iltrol and thestability of the treated oil determined. The following data wereobtained.

TABLE 5 Stabilization of Hydrocracked Lubes by Slurry The above datashow that slurrying the oil with the adsorbent followed by filteringimproves the stability of the oil somewhat but not to any outstandingdegree. The data also show that the cracking catalyst is no better thanFiltrol when using the slurrying technique.

The nature and advantages of the present invention having thus beenfully set forth and specific examples of the same given, what is claimedas new, useful and unobvious and desired to be secured by Letters Patentis:

1. A process for forming a lubricating oil fraction resistant todeterioration upon exposure to light and air which comprises contactinga hydrocarbon fraction, at hydrocracking conditions, with ahydrocracking catalyst to form a plurality of fractions includinglubricating oil fractions, dewaxing said lubricating oil fractionspercolating said dewaxed lubricating oil fractions with a Y-zeolite,said Y-zeolite being physically combined with an amorphous crackingcatalyst containing a major amount of silica and a minor amount ofalumina, and recovering a light and air stable lubricating oil fraction.

2. The process of claim 1 in which the hydrocracking step takes place ata temperature between 700 and 900 F., at a pressure above 1,500 psig anda space velocity below 1 V/V/Hr.

3. The process of claim 1 in which said Y-zeolite is faujasite having asilica/alumina mole ratio greater than 3/1 and uniform pore openings ofabout 6 to A.

4. The process of claim 2 in which said hydrocracking catalyst is anoxide or sulfide of a metal chosen from the group consisting of GroupVB, VIB and VIII of the Periodic System and mixtures thereof.

5. A process of forming a lubricating oil fraction resistant todeterioration upon exposure to light and air which comprises contactinga hydrocarbon fraction, at hydrocracking conditions, with ahydrocracking catalyst to form a plurality of fractions includinglubricating oil fractions, percolating said lubricating oil fractions attemperature below 150 F. with a catalyst comprising silica-alumina gelmatrix containing Y- zeolite and recovering a light and air stablelubricating oil fraction.

6. The process of claim 5 in which said silica-alumina gel matrixcontaining Yzeolite is a physically combined mixture of an amorphouscracking catalyst containing a major amount of silica and a minor amountof alumina and said Y-zeolite.

7. The process of claim 5 in which said Y-zeolite is faujasite having asilica-alumina mole ratio greater than about Bill and uniform poreopenings of about 6 to 15 A.

8. The process of claim 5 in which said silica-alumina gel matrixcontaining Y-zeolite consists of wt. percent of a mixture of Al,O,/Si0,,in the proportion of 13 wt. Al,0 and 87 wt. SiO,, with 5 wt. percentfaujasite.

9. The process of claim 5 wherem said silica-alumina gel matrixcontaining Y-zeolite is regenerated by washing with benzene.

10. The process of claim 5 wherein said lubricating oil fractions aredewaxed prior to contact with said silica-alumina gel matrix containingY-zeolite.

11. A process for fonning a stabilized lubricating oil fractionresistant to deterioration upon exposure to light and air comprisingsubjecting a high boiling hydrocarbon fraction to hydrocrackingconditions in the presence of a hydrocracking catalyst to form aplurality of fractions including lubricating oil fractions boiling aboveabout 650 F., dewaxing said lubricating oil fractions, percolating atleast a portion of said dewaxed lubricating oil fractions through acatalyst comprising silica-alumina gel matrix containing Y-zeolite andrecovering a light and air stable lubricating oil fraction.

12. The process of claim 11 in which said silica-alumina gel matrixcontaining Y-zeolite is a physically combined mixture of an amorphouscracking catalyst containing a major amount of silica and a minor amountof alumina and said Y-zeolite.

13. The process of claim 11 in which said Y-zeolite is faujasite havinga silica-alumina mole ratio greater than about 3/1 and uniform poreopenings of about 6 to 15 A.

14. The process of claim 11 in which said silica-alumina gel matrixcontaining Y-zeolite consists of 95 wt. percent of a mixture of ALOJSiQ,in the proportion of 13 wt. k ALO, and 87 wt. SiO, with 5 wt. percentfaujasite.

15. The process of claim 11 wherein said silica-alumina gel matrixcontaining Y-zeolite is regenerated by washing with benzene.

16. The process of claim 11 wherein said percolation is conducted at atemperature less than about F.

I i i t i

2. The process of claim 1 in which the hydrocracking step takes place ata temperature between 700* and 900* F., at a pressure above 1,500 psigand a space velocity below 1 V/V/Hr.
 3. The process of claim 1 in whichsaid Y-zeolite is faujasite having a silica/alumina mole ratio greaterthan 3/1 and uniform pore openings of about 6 to 15 A.
 4. The process ofclaim 2 in which said hydrocracking catalyst is an oxide or sulfide of ametal chosen from the group consisting of Group VB, VIB and VIII of thePeriodic System and mixtures thereof.
 5. A process of forming alubricating oil fraction resistant to deterioration upon exposure tolight and air which comprises contacting a hydrocarbon fraction, athydrocracking conditions, with a hydrocracking catalyst to form aplurality of fractions including lubricating oil fractions, percolatingsaid lubricating oil fractions at temperature below 150* F. with acatalyst comprising silica-alumina gel matrix containing Y-zeolite andrecovering a light and air stable lubricating oil fraction.
 6. Theprocess of claim 5 in which said silica-alumina gel matrix containingY-zeolite is a physically combined mixture of an amorphous crackingcatalyst containing a major amount of silica and a minor amount ofalumina and said Y-zeolite.
 7. The process of claim 5 in which saidY-zeolite is faujasite having a silica-alumina mole ratio greater thanabout 3/1 and uniform pore openings of about 6 to 15 A.
 8. The processof claim 5 in which said silica-alumina gel matrix containing Y-zeoliteconsists of 95 wt. percent of a mixture of Al2O3/SiO2, in the proportionof 13 wt. % Al2O3 and 87 wt. % SiO2, with 5 wt. percent faujasite. 9.The process of claim 5 wherein said silica-alumina gel matrix containingY-zeolite is regenerated by washing with benzene.
 10. The process ofclaim 5 wherein said lubricating oil fractions are dewaxed prior tocontact with said silica-alumina gel matrix containing Y-zeolite.
 11. Aprocess for forming a stabilized lubricating oil fraction resistant todeterioration upon exposure to light and air comprising subjecting ahigh boiling hydrocarbon fraction to hydrocracking conditions in thepresence of a hydrocracking catalyst to form a plurality of fractionsincluding lubricating oil fractions boiling above about 650* F.,dewaxing said lubricating oil fractions, percolating at least a portionof said dewaxed lubricating oil fractions through a catalyst comprisingsilica-alumina gel matrix containing Y-zeolite and recovering a lightand air stable lubricating oil fraction.
 12. The process of claim 11 inwhich said silica-alumina gel matrix containing Y-zeolite is aphysically combined mixture of an amorphous cracking catalyst containinga major amount of silica and a minor amount of alumina and saidY-zeolite.
 13. The process of claim 11 in which said Y-zeolite isfaujasite having a silica-alumina mole ratio greater than about 3/1 anduniform pore openings of about 6 to 15 A.
 14. The process of claim 11 inwhich said silica-alumina gel matrix containing Y-zeolite consists of 95wt. percent of a mixture of Al2O3/SiO2, in the proportion of 13 wt. %Al2O3 and 87 wt. % SiO2 with 5 wt. percent faujasite.
 15. The process ofclaim 11 wherein said silica-alumina gel matrix containing Y-zeolite isregenerated by washing with benzene.
 16. The process of claim 11 whereinsaid percolation is conducted at a temperature less than about 150* F.